Bamboo is one of the fast growing perennial grasses. Individual rods of bamboo, referred to as culm, are divided into sections by joints or knobs referred to as nodes. In many parts of the world, bamboo is utilized as a low-cost construction material. When individual rods are utilized as a reinforcement member for concrete or cementitious bodies, the bamboo absorbs moisture from the fresh concrete. As bamboo absorbs the water, swelling occurs, and the volume of the bamboo increases. If the swelling pressure is large enough, the bamboo pushes the wet concrete aside. At the end of the curing period, (approximately 21 days), the concrete becomes hard, the bamboo has lost its water and shrinks, leaving voids between the bamboo rod surface and the concrete.
Such voids can trap air, moisture, and other foreign materials which will accelerate decay of the bamboo rod, causing cracks in the structure. Also, voids lead to a loss of bond, or adherence, between the bamboo and surrounding concrete.
It is well known to coat the bamboo rods with various materials, such as paint, tar, cement, and asphalt emulsion, in order to reduce the water absorption potential of bamboo. Unfortunately such techniques are either too expensive or ineffective due to difficulty of application.
Therefore, there is a need for a treated bamboo which can resist swelling due to absorption of moisture, and thereby prevent loss of bond with surrounding concrete in a reinforced concrete body.